1. Field of the Invention
The present invention generally relates to a heat dissipating assembly and, more particularly, to a heat dissipating assembly that is simple in structure and that can be manufactured at low costs.
2. Description of the Related Art
FIGS. 1-3 show a conventional heat dissipating assembly 9 including a circuit board 91, a plurality of heat generating elements 92, a heat spreader plate 93, and a heat dissipating unit 94. A plurality of contacts 911 is provided on a side of the circuit board 91 and electrically connected to the heat generating elements 92. The heat spreader plate 93 includes first and second faces 931 and 932. The circuit board 91 is engaged with the first face 931 of the heat spreader plate 93 by heat pressing, adhering, or screwing. The heat spreader plate 93 is made of aluminum having excellent thermal conductivity and low specific gravity. The heat dissipating unit 94 is a metal heat sink and is firmly bonded to the second face 932 of the heat spreader plate 93 by a heat-conducting binding layer 95 of adhesive with excellent heat conductivity. The heat dissipating unit 94 includes a plurality of spaced fins 941 on a surface not engaged with the heat spreader plate 93.
With reference to FIGS. 2 and 3, the heat generated during operation of the heat generating elements 92 is transmitted to and absorbed by the heat spreader plate 93 via the circuit board 91. The heat is then transmitted to the heat dissipating unit 94. The fins 941 increase the heat dissipating area and thus enhances the heat dissipating efficiency, avoiding damage to or degraded performance of the heat generating elements 92 due to excessively high working temperature.
The heat conducting efficiency is poor, because the heat generated by the heat generating elements 92 must be transmitted through many members including the circuit board 91, the heat spreader plate 93, and the heat-conducting binding layer 95 made of different materials before heat exchange occurs at the fins 941 of the heat dissipating unit 94. The circuit board 91 made of insulating material further decreases the heat conducting efficiency. Furthermore, the heat dissipating assembly 9 has many members and thus has high manufacturing costs. Further, the heat spreader plate 93 and the heat dissipating unit 94 are both made of metal material and thus, require the heat-conducting binding layer 95 to provide reliable engagement therebetween. Further, the circuit board 91 must be engaged with the first face 931 of the heat spreader plate 93 by heat pressing, adhering, or screwing. All of these increase the complexity and difficulties in assembling the heat dissipating assembly 9. The production/assembling efficiency is thus low. Thus, a need exists for an improved heat dissipating assembly.